This invention relates to nutritional formulations containing prebiotic substances and the use of such formulations in the growth promotion of beneficial microorganisms and the inhibition of pathogenic organisms. More specifically, this invention relates to nutritional formulations containing oligofructose and sialyllactose.
Oligofructose is a series of natural oligosaccharides found primarily in vegetables, such as onion and the root of the chicory plant. Oligofructose is known to be a specific substrate for Bifidobacteria. (See, e.g., Mitsuoka et al, xe2x80x9cEffect of Fructo-oligosaccharides on Intestinal Microfloraxe2x80x9d, Die Nahrung, 3, 5-6: 427-436 (1987)).
Oligofructose passes through the small intestine without being digested, reaching the large intestine. In the large intestine, oligofructose is fermented only by a limited range of microorganisms that include most species of Bifidobacteria, i.e., species of bacteria beneficial for human health. (See Bouhnik et al, xe2x80x9cShort Chain Fructo-Oligosaccharide Administration Dose-Dependently Increases Fecal Bifidobacteria in Healthy Humans,xe2x80x9d J. Nutrition, 129:113-116).
For example, oligofructose can be utilized efficiently by Lactobacilli and Bifidobacteria. It is known that in mixed populations of bacteria such as that which exists in the human colon, oligofructose is consumed preferentially by Bifidobacteria. The other bacteria present in this xe2x80x9cmixed populationxe2x80x9d either do not grow or are inhibited from growing. (See, e.g., Gibson et al, xe2x80x9cSelective Stimulation of Bifidobacteria in the Human Colon, by oligofructose and Insulin.xe2x80x9d Gastroenterol, 108:975-982 (1995)).
Moreover, it is known that a metabolic by-product of Bifidobacteria is short chain fatty acids, resulting in a reduction of the pH in the digestive tract. This pH effect has been observed clinically and documented in Mitsuoka et al, xe2x80x9cEffect of Fructo-oligosaccharides on Intestinal Microfloraxe2x80x9d, Die Nahrung, 3,5-6: 427-438 (1987).
Sialyllactoses are oligosaccharides which occur naturally in human milk as well as in milk of other mammals. However, sialyllactoses are present at noticeably higher concentrations in human milk compared to other mammalian species.
The two primary species of sialyllactose are 3xe2x80x2-sialyllactose and 6xe2x80x2-sialyllactose. These species occur naturally in human milk at a relative ratio of 1:3 (3xe2x80x2:6xe2x80x2). Sialyllactose is known to have anti-adhesive properties for specific pathogenic bacteria. For example, it has been suggested that sialyllactose acts to inhibit cholera toxin (see, Idota et al, xe2x80x9cInhibition of Cholera Toxin by Human Milk Fractions and Sialyllactose,xe2x80x9d Biosci. Biotech. Biochem. 59:417-419) and Helicobacter pylori (see, Simon et al, xe2x80x9cInhibition of Helicobacter pylori Binding to Gastrointestinal Epithelial Cells by Sialic Acid-Containing Oligosaccharides,xe2x80x9d Infection and Immunity, 750-757, (1997)). In light of its antiadhesive properties, sialyllactose has been used to treat a number of medical conditions. For example, U.S. Pat. Nos. 5,514,660 and 5,753,630, describe the use of sialyllactose in the treatment and inhibition of duodenal ulcers. U.S. Pat. No. 5,883,079 describes the use of sialyllactose to inhibit H. pylori infection in mammalian tissue.
However, the use of two prebiotic substances, specifically, oligofructose and sialyllactose, in combination has heretofore not been described. Accordingly, it can be seen that there is a need for such a combination.
The present invention is related to a nutritional composition, which is effective in increasing beneficial Bifidobacteria and inhibiting the binding of pathogenic microorganisms to human tissue. More specifically, the present invention is directed to nutritional compositions comprising oligofructose and sialyllactose. The present invention is further directed to a method of increasing the concentration of Bifidobacteria and inhibiting the binding of pathogenic bacteria in a human subject comprising enterally administering to said subject a composition comprising oligofructose and sialyllactose.